Abstract
OBJECTIVES: This study aimed to elucidate the relationship between preserved ratio impaired spirometry (PRISm) and risk of frailty and to identify potential risk factors. DESIGN: Cross-sectional study. SETTING: The National Health and Nutrition Examination Survey 2007-2012. PARTICIPANTS: A total of 6769 participants aged 40-85 years were included in this study: 1042 with PRISm, 702 with chronic obstructive pulmonary disease (COPD) and 5025 with non-PRISm/COPD. EXPOSURE AND OUTCOME MEASURES: Frailty was evaluated using a frailty index, categorising participants into non-frail (score <0.21) and frail (score ≥0.21). Weighted logistic regression with multivariable adjustment was conducted to investigate the relationship between PRISm and frailty as well as to identify risk factors. RESULTS: The prevalence of frailty significantly differed among the three cohorts (p<0.0001), with PRISm patients and COPD patients exhibiting higher rates (32.4% and 30.4%, respectively) than the non-PRISm/COPD group (13.6%). In the unadjusted models, PRISm patients exhibited a threefold increased risk of frailty (OR 3.03, 95% CI 2.47 to 3.72), similar to COPD patients (OR 2.77, 95% CI 2.19 to 3.50). Adjusted models confirmed a comparable risk of frailty in PRISm patients (OR 1.42, 95% CI 1.09 to 1.83) and COPD patients (OR 1.65, 95% CI 1.17 to 2.32). The findings remained robust across sensitivity and subgroup analyses. Risk factors for frailty among PRISm patients included female sex, non-Hispanic black and other races, higher body mass index, smoking history, diabetes and cardiovascular disease. CONCLUSION: PRISm has a similar prevalence and risk of frailty as COPD, both of which are greater than those of non-PRISm/COPD. This highlights the importance of frailty in patients with PRISm.